here is what i got from a 737 pilot.
stall: loud bang and high egt
surge: large fluctuations in power (N1), high egt. accompanied by a loud bang
severe damage: main thing to look out for is unusually high vibrations and loss of N1.
seperation: loss of both N1 and N2 indication. Both these indications will be blank.
Any one care to correct or add anything else?